code: def test_get_default_exprs(self):
      col = "col"
  
      default_exprs = HiveStatsCollectionOperator(
          **self.kwargs
      ).get_default_exprs(col, None)
  
      assert default_exprs == {(col, "non_null"): f"COUNT({col})"}
  
imports: from __future__ import annotations
  import os
  import re
  from unittest.mock import MagicMock, patch
  import pytest
  from airflow.exceptions import AirflowException
  from airflow.providers.apache.hive.operators.hive_stats import HiveStatsCollectionOperator
  from airflow.providers.presto.hooks.presto import PrestoHook
  from tests.providers.apache.hive import DEFAULT_DATE, DEFAULT_DATE_DS, MockConnectionCursor, MockHiveMetastoreHook, MockMySqlHook, TestHiveEnvironment
label_desc: Use image node_id 2 for calling the TestHiveStatsCollectionOperator obj's underlying member method code with example usage: obj.test_get_default_exprs() without return types